Javascript 不确定Google Maps的侦听器事件中值为何未定义

我试图从数组数组中获取字符串。我想在信息窗口中获取第一个属性[0]。我可以使用第二个和第三个值来设置标记的位置，还可以console.log第一个值

具体的JavaScript代码如下所示：

markers = [
["4841 Bethesda Avenue (Elm Street)", 38.980724, -77.0964],
["7171 Woodmont Avenue", 38.980097, -77.093662],
["921 Wayne Avenue", 38.995740, -77.025652],
["801 Ellsworth Drive",38.997778, -77.025071]
];

infoWindow = new google.maps.InfoWindow()

for (var i = 0; i < markers.length; i++) {
    console.log("markers: " + markers[i][0]);
    position = new google.maps.LatLng(markers[i][1], markers[i][2]);
    marker = new google.maps.Marker({
        position: position, 
        map: map,
        title: markers[i][0]
    });
    console.log("markers 2: " + markers[i][0]);
    google.maps.event.addListener(marker, 'click', function () {
        infoWindow.setContent("<div>Hello, World" + markers[i][0] + "</div>");
        infoWindow.open(map, this);
    });
};

CSS:

JavaScript:

var map;
var mapProp;
var marker;
var markers;
var url;
var myData;
var time;
var available;
var total;
var facility;
var position;
var infoWindow;

function initialize() {
    mapProp = {
        center: new google.maps.LatLng(38.994890, -77.063416),
        zoom: 13,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };
    map = new google.maps.Map(document.getElementById("map"), mapProp);
}
$(document).ready(function() {
    initialize();
    url = 'https://data.montgomerycountymd.gov/resource/qahs-fevu.json';
    $.getJSON(url, function(data) {
        myData = data;
        for (i = 0; i < myData.length; i++) {
            time = (myData[i].asofdatetime).slice(11);
            available = myData[i].space_count;
            total = myData[i].total_spaces;
            facility = myData[i].facilitynumber;
            if (facility === "GAR 57") {
                facility = "4841 Bethesda Avenue (Elm Street)";
                $('#GAR57').html('As of ' + time + ' there are ' + available +
                    ' of ' + total + ' at ' + facility);
            } else if (facility === "GAR 31") {
                facility = "7171 Woodmont Avenue";
                $('#GAR31').html('As of ' + time + ' there are ' + available +
                    ' of ' + total + ' at ' + facility);
            } else if (facility === "GAR 60") {
                facility = "921 Wayne Avenue";
                $('#GAR60').html('As of ' + time + ' there are ' + available +
                    ' of ' + total + ' at ' + facility);
            } else {
                facility = "801 Ellsworth Drive";
                $('#GAR61').html('As of ' + time + ' there are ' + available +
                    ' of ' + total + ' at ' + facility);
            }
        }
    });
    //set markers
    markers = [
        ["4841 Bethesda Avenue (Elm Street)", 38.980724, -77.0964],
        ["7171 Woodmont Avenue", 38.980097, -77.093662],
        ["921 Wayne Avenue", 38.995740, -77.025652],
        ["801 Ellsworth Drive", 38.997778, -77.025071]
    ];
    infoWindow = new google.maps.InfoWindow();
    for (var i = 0; i < markers.length; i++) {
        console.log("markers: " + markers[i][0]);
        position = new google.maps.LatLng(markers[i][1], markers[i][2]);
        marker = new google.maps.Marker({
            position: position,
            map: map,
            title: markers[i][0]
        });
        console.log("markers 2: " + markers[i][0]);
        google.maps.event.addListener(marker, 'click', function() {
            infoWindow.setContent("<div>Hello, World" + markers[i][0] + "</div>");
            infoWindow.open(map, this);
        });
    };
});

var映射；
var-mapProp；
var标记；
var标记；
var-url；
var-myData；
var时间；
可用的var；
总风险价值；
风险价值工具；
var位置；
var信息窗口；
函数初始化（）{
mapProp={
中心：新google.maps.LatLng（38.994890，-77.063416），
缩放：13，
mapTypeId:google.maps.mapTypeId.ROADMAP
};
map=新的google.maps.map（document.getElementById（“map”），mapProp）；
}
$（文档）.ready（函数（）{
初始化（）；
url='1〕https://data.montgomerycountymd.gov/resource/qahs-fevu.json';
$.getJSON（url、函数（数据）{
myData=数据；
对于（i=0；i

标记[i][0]变得未定义，因为它不存在于addListener中的函数范围内，即您没有将标记传递到函数中

相反，你是通过了标记

for（变量i=0；i

---

显示了单击标记时显示标题的示例。我假设这就是您想要实现的。

使用@geocodezip中的代码函数闭包

（marker，I）

在函数末尾做了什么？这些是匿名函数的参数，该匿名函数返回click listener函数（`（function（marker，I）{return function（）{`

#map {
    height: 300px;
    width: 500px;
    margin: 0 auto;
    border: 1px solid black;
}

var map;
var mapProp;
var marker;
var markers;
var url;
var myData;
var time;
var available;
var total;
var facility;
var position;
var infoWindow;

function initialize() {
    mapProp = {
        center: new google.maps.LatLng(38.994890, -77.063416),
        zoom: 13,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };
    map = new google.maps.Map(document.getElementById("map"), mapProp);
}
$(document).ready(function() {
    initialize();
    url = 'https://data.montgomerycountymd.gov/resource/qahs-fevu.json';
    $.getJSON(url, function(data) {
        myData = data;
        for (i = 0; i < myData.length; i++) {
            time = (myData[i].asofdatetime).slice(11);
            available = myData[i].space_count;
            total = myData[i].total_spaces;
            facility = myData[i].facilitynumber;
            if (facility === "GAR 57") {
                facility = "4841 Bethesda Avenue (Elm Street)";
                $('#GAR57').html('As of ' + time + ' there are ' + available +
                    ' of ' + total + ' at ' + facility);
            } else if (facility === "GAR 31") {
                facility = "7171 Woodmont Avenue";
                $('#GAR31').html('As of ' + time + ' there are ' + available +
                    ' of ' + total + ' at ' + facility);
            } else if (facility === "GAR 60") {
                facility = "921 Wayne Avenue";
                $('#GAR60').html('As of ' + time + ' there are ' + available +
                    ' of ' + total + ' at ' + facility);
            } else {
                facility = "801 Ellsworth Drive";
                $('#GAR61').html('As of ' + time + ' there are ' + available +
                    ' of ' + total + ' at ' + facility);
            }
        }
    });
    //set markers
    markers = [
        ["4841 Bethesda Avenue (Elm Street)", 38.980724, -77.0964],
        ["7171 Woodmont Avenue", 38.980097, -77.093662],
        ["921 Wayne Avenue", 38.995740, -77.025652],
        ["801 Ellsworth Drive", 38.997778, -77.025071]
    ];
    infoWindow = new google.maps.InfoWindow();
    for (var i = 0; i < markers.length; i++) {
        console.log("markers: " + markers[i][0]);
        position = new google.maps.LatLng(markers[i][1], markers[i][2]);
        marker = new google.maps.Marker({
            position: position,
            map: map,
            title: markers[i][0]
        });
        console.log("markers 2: " + markers[i][0]);
        google.maps.event.addListener(marker, 'click', function() {
            infoWindow.setContent("<div>Hello, World" + markers[i][0] + "</div>");
            infoWindow.open(map, this);
        });
    };
});

 for (var i = 0; i < markers.length; i++) {
    console.log("markers: " + markers[i][0]);
    position = new google.maps.LatLng(markers[i][1], markers[i][2]);
    marker = new google.maps.Marker({
        position: position, 
        map: map,
        title: markers[i][0]
    });
    console.log("markers 2: " + marker.title);
    google.maps.event.addListener(marker, 'click', function () {
        infoWindow.setContent("<div>Hello, World " + marker.title + "</div>");
        infoWindow.open(map, this);
    });
};